Prepaying 2018 state income taxes is blocked in GOP bill

Jabin Botsford | The Washington Post | Getty Images

Chairman of the House Ways and Means Committee Rep. Kevin Brady, R-Texas, talks with President Donald Trump during a meeting on tax policy with Republican lawmakers in the Cabinet Room of the White House in Washington, DC on Thursday, Nov. 02, 2017.

Under the bill, the standard deduction would nearly double for all taxpayers before returning to current law in 2026. This means starting next year, an individual would need total deductions to exceed $12,000, the tax bill’s new standard deduction for individual taxpayers, up from the current $6,350.

Married couples filing jointly would need deductions worth more than their new standard deduction of $24,000 under the bill, which is up from $12,700 for 2017; for heads of households, it’s $18,000, up from $9,350 this year.

About 49 million taxpayers, or 28 percent, currently itemize, according to the Urban-Brookings Tax Policy Center. If the bill is approved, it’s likely even fewer taxpayers would do so.

More from CNBC Personal Finance:

GOP tax bill expands medical expense deduction for two years

Find your new tax brackets under the final GOP tax plan

Final tax plan leaves popular stock sale strategies untouched

(Correction: A previous version of this story incorrectly stated that property taxes could not be prepaid.)